In order to make aircraft passengers comfortable, and in order to transport them between an airport terminal building and an aircraft in such a way that they are protected from the weather and from other environmental influences, passenger boarding bridges are used which are telescopically extensible and the height of which is adjustable. For instance, an apron drive bridge includes a plurality of adjustable modules, including: a rotunda, a telescopic tunnel, a bubble section, a cab, and elevating columns with wheel carriage. Other common types of passenger boarding bridges include radial drive bridges and over-the-wing (OTW) bridges.
Historically, the procedure for guiding an aircraft to a stopping position adjacent to the passenger boarding bridge has been time consuming and labor intensive. In general, the pilot taxis the aircraft along a lead-in line to the stopping position. Typically, the lead-in line is a physical marker that is painted onto the apron surface, and is used for guiding the aircraft along a predetermined path to the stopping position. Additional markings in the form of stop lines, different ones for different types of aircraft, are provided at predetermined positions along the lead-in line. Thus, when the nose gear of a particular type of aircraft stops precisely at the stop line for that type of aircraft, then the aircraft is known to be at its stopping position. Of course, the pilot's view of the apron surface from the cockpit of an aircraft is limited. This is particularly true for larger aircraft, such as for instance a Boeing 747-X00. Typically, in order to follow the lead-in line the pilot has relied upon instructions that are provided by a human ground marshal or guide man, together with up to two “wing walkers”. Optionally, stop bars are located on a pole that is fixedly mounted to the ground surface, including appropriate stop bars for each type of aircraft that uses the gate. Alternatively, a tractor or tug is used to tow the aircraft along the lead-in line to its stopping position.
More recently, sophisticated Visual Docking Guidance Systems have been developed to perform the function of the human ground marshal or guide man and wing walkers. In particular, a Visual Docking Guidance System (VDGS) senses the aircraft as it approaches the stopping position and provides instructions to the pilot via an electronic display device. The electronic display device is mounted at a location that makes it highly visible to the pilot when viewed from the cockpit of an aircraft. Typically, the instructions include a combination of alphanumeric characters and symbols, which the pilot uses to guide the aircraft precisely to the stopping position for the particular type of aircraft. The high capital cost of the VDGS is offset by reduced labor costs and the efficiency that results from stopping the aircraft as precisely as is possible under the guidance of a human ground marshal or guide man.
One common feature of the types of VDGS that are in use today is that a sensor is provided at a position that is typically approximately aligned with the lead in-line. Typical sensors include digital still or video cameras, laser imaging devices, or infrared sensors. The sensor is used to scan an area that is adjacent to the passenger boarding bridge, so as to “look” for an approaching aircraft. Based on sensed features of the approaching aircraft, the VDGS either identifies the aircraft type or merely confirms that the aircraft type matches information that was provided previously. Once the aircraft type is confirmed, and thus the relevant stopping position is known, the sensor continues to “watch” the aircraft as it approaches the stopping position, and provides instructions to the pilot for guiding the aircraft to the stopping position. A combination of a sophisticated imaging system and a complex image data processing algorithm is required in order to ensure that the aircraft type is identified correctly, and that once identified, the trajectory of the aircraft is monitored in real time and with sufficient accuracy to enable proper parking of the aircraft. Of course, from time to time the aircraft type will be identified incorrectly, or the identified type will not agree with the information that was provided previously. In those cases, the pilot must rely upon one of the more traditional procedures for parking the aircraft discussed supra. In addition, unfavorable environmental conditions such as fog, heavy rain, snow etc. may render the imager of the VDGS ineffective. Under such unfavorable conditions, the pilot must once again rely upon one of the more traditional procedures for parking the aircraft discussed supra.
Accordingly, there exists an unfulfilled need for a system and method for identifying and guiding an aircraft to a stopping position. There furthermore exists an unfulfilled need for such a system and method, which provides reliable operation even under unfavorable environmental conditions such as fog, heavy rain, snow etc., and that reduces the potential for incorrectly identifying the aircraft type to be parked.